(PowerShell) Verify a .p7m and get Algorithm Information

Demonstrates how to verify a .p7m and then examine the algorithms used by the signature.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$crypt = New-Object Chilkat.Crypt2

$inFile = "qa_data/p7m/brainpoolP256r1.p7m"
$outFile = "qa_output/something.dat"

# Verify and extract the signed data.
$success = $crypt.VerifyP7M($inFile,$outFile)
if ($success -eq $false) {
    $($crypt.LastErrorText)
    exit
}

# Examine details about the signature(s)
$json = $crypt.LastJsonData()
$json.EmitCompact = $false
$($json.Emit())

# Sample output

# {
#   "pkcs7": {
#     "verify": {
#       "digestAlgorithms": [
#         "sha256"
#       ],
#       "signerInfo": [
#         {
#           "cert": {
#             "serialNumber": "FFFFE552B302FFFFFF1E34C3ACEB2FFFF",
#             "issuerCN": "The common name of the cert...",
#             "issuerDN": "",
#             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
#             "digestAlgName": "SHA256"
#           },
#           "contentType": "1.2.840.113549.1.7.1",
#           "signingTime": "190409140500Z",
#           "messageDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
#           "signingAlgOid": "1.2.840.10045.4.3.2",
#           "signerDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
#           "authAttr": [
#             {
#               "oid": "1.2.840.113549.1.9.3",
#               "oidName": "contentType"
#             },
#             {
#               "oid": "1.2.840.113549.1.9.5",
#               "oidName": "signingTime"
#             },
#             {
#               "oid": "1.2.840.113549.1.9.52",
#               "oidName": "1.2.840.113549.1.9.52",
#               "der": "MBs ... AwI="
#             },
#             {
#               "oid": "1.2.840.113549.1.9.4",
#               "oidName": "messageDigest"
#             },
#             {
#               "oid": "1.2.840.113549.1.9.16.2.47",
#               "oidName": "signingCertificateV2",
#               "der": "MCYw .. 7PlQ=="
#             },
#             {
#               "oid": "1.2.840.113549.1.9.20",
#               "oidName": "1.2.840.113549.1.9.20"
#             }
#           ]
#         }
#       ]
#     }
#   }
# }

# Code for parsing the above JSON...

$i = 0
$count_i = $json.SizeOfArray("pkcs7.verify.digestAlgorithms")
while ($i -lt $count_i) {
    $json.I = $i
    $strVal = $json.StringOf("pkcs7.verify.digestAlgorithms[i]")
    $i = $i + 1
}

$i = 0
$count_i = $json.SizeOfArray("pkcs7.verify.signerInfo")
while ($i -lt $count_i) {
    $json.I = $i
    $certSerialNumber = $json.StringOf("pkcs7.verify.signerInfo[i].cert.serialNumber")
    $certIssuerCN = $json.StringOf("pkcs7.verify.signerInfo[i].cert.issuerCN")
    $certIssuerDN = $json.StringOf("pkcs7.verify.signerInfo[i].cert.issuerDN")
    $certDigestAlgOid = $json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid")
    $certDigestAlgName = $json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName")
    $contentType = $json.StringOf("pkcs7.verify.signerInfo[i].contentType")
    $signingTime = $json.StringOf("pkcs7.verify.signerInfo[i].signingTime")
    $messageDigest = $json.StringOf("pkcs7.verify.signerInfo[i].messageDigest")
    $signingAlgOid = $json.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid")
    $signerDigest = $json.StringOf("pkcs7.verify.signerInfo[i].signerDigest")
    $j = 0
    $count_j = $json.SizeOfArray("pkcs7.verify.signerInfo[i].authAttr")
    while ($j -lt $count_j) {
        $json.J = $j
        $oid = $json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].oid")
        $oidName = $json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].oidName")
        $der = $json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].der")
        $j = $j + 1
    }

    $i = $i + 1
}

$("Success!")